Rotary drier



G. ENGEL. SR

ROTARY DRIER Filed Sept. 18 1920 lll llllv titl application niet. llepteinner 1t, little. aerial lle. allaite.

f'o all autom it may concern:

be it knovvn that l9 blonnr Errani,2 du., a citiaen of the llnited @taten and a resident of brooklyn, linings ountyl, and State of hlevv lork., have invented certain nevv and useful llmprovernents in tar Driers, of vvhich the follovving is a speci mation.,

lllly present invention relates particularly to driers of the rotary type., and the objects of the invention are to secure a more rapid interchange of heat and to utilize to a large ertent that heat which heretofore has been vvasted.

@ther objects are to prevent overheating.

of the apparatus, vvhile at the saine time facilitating the interchange of heat and, as a part of the same operation, to promote the combustion at the source of the heat..

rllhese objects l have attained by a novel construction, combination and arrangement of parts, one example 'of which is disclosed in the accompanying drawing wherein there is illustrated in vertical sectional vievv, a drier made in accordance vvith the invention.

lin the construction illustrated, the material under treatment is fed into the upper end of a dovvnvvardly inclined rotating drurn or conveyer cylinder 1 from a hopper 2 and is collected at the discharge end of the cylinder by a chute 3, which delivers the product onto a carrying-od conveyer l. This conveyer drum is shovvn as rotatably supported on suitable bearings at 5 and t, and as driven by suitable gearing l.

'lhe heat is supplied, in the illustration, by a fuel burning furnace il connected by a duct 9 with the heating or furnace chamber 10 through which the drying cylinder errtends.

lin the furnace chamber above the cylinder is an air preheater shovvn as consisting of a series of tubes or flues 11 open at the opposite ends to the chambers 12 and 13.

Partitions or bridge vvalls 1d and 15 are shovvn as provided in the furnace charnber for dedecting the heat products from the furnace in a'circuitous path up around the `cylinder and about the preheating tubes, thence down around said tubes and cylinder and again up around the cylinder and tubes to the outlet due 1t which leads to a suitable take-olf 1l'9 vvhich latter may be connected with a stack.,

.'llhe chamber 12 is shown as open to the air at le to forni an intake for fresh air and errtendin vvithin said chamber, is one end of a doule ended flovv reversing valve 19 pivoted at all and adapted to be throvvn4 to cooperate vvith a partition vvall 21 in the full line position shovvn, or to cooperate with the lovver vvall 22, as indicated in dotted lines. lin the first or full line position, one vving of this valve cuts od" entrance of air to 'the lovver set of tubes., and the other vving of the valve shuts oil' the exhaust due Q3, the lovver set of tubes being left open at such a time to the chamber 2d at the discharge end of the drier cylinder. lin the reverse or dotted line position, the lovver wing of the valve opens up the lovver set of tubes to atmosphere, cuts off the tubes from the chamber @l and opens up this chamber to the eirhaust Hue 23.

dit the opposite end of the preheater tubes, there is provided a double Winged valve 25 pivoted at Q6 and controlling flow between the end chamber 13 and a chamber- 27 which is open to the inlet end of the cylinder..

The tvvo valves described ordinarily stand in the positions shovvn in full lines and they are preferably connected so as to operate, in unison as by means of a rod Q8 engaged vvith crank arms Q9 and 80, attached to the respective valves. ln the position referred to, the circulation through the preheater will be as indicated in the solid line arrows, the air being induced at the chamber 1Q into the set of tubes above the partition 21 and pass- "ting from said tubes by vvay of the chamber 13 at the opposite end of the apparatus through the lower set of tubes and into the chamber 2li at the discharge end of the conveyer. This air, vvhich has been preheated in its circulation through the tubes, passes on an upvvard incline through the conveyer cylinder, absorbing moisturefrorn the inaterial in the conveyer during such dow.

'lhe more or less moisture-laden air discharges from the upper or entrance end of the -conveyer into the chamber 27, and a special feature of the yinvention consists in lill llll

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lilik further utilizing this air by passing the same downward through a duct. or ducts 31 beneath the grate or into the combustion chamber of the furnace. This flow of combustion supporting gas ma be governed by a damper 32 inserted in tie upper portion of the duct or conduit 31.

By the arrangement described, it will be seen that the material in the drying c linder is subjected to the drying influence o a current of air passing over the material under treatment counter to its flow through the conveyer;v that this drying air is heated to more readily absorb moisture; that such heat is derived for the greater part from the waste products of the furnace, that the vapor-laden air is used to promote combustion at the furnace, and that the vapors produced from the moisture evaporated are returned combined or included with the gases of combustion into heating relation to the drying chamber, wherefore a greater volume of lactual lheat is supplied to the drier and at a lower temperature than would be the case if the gases of combustion alone were being used.

Thus, in additionto the increased heat transfer, the apparatus on account of the lower temperature at which it operates, .is more durable and will stand up better in actual use. The vapor charged air passing through the furnace promotes combustion and in the case of a coal fire, prevents elinkers. It also has the effect of increasing the total heat while reducing the sensible heat of the gas leaving the furnace, this arising from the fact that the specific heat of the vapors is greater than of gas.

To force the drier, the dampers may be shifted to the dotted line positions indicated` in which event, air will be taken into all of the preheater tubes and discharged from chamber 13 directly into chamber 27 at the entrance end of the conveyer drum, the full volume of air thus heated passing through and out the discharge end of the drum up t-he exhaust ue 23 as indicated by the broken line arrows. In this event, air for combustion may be supplied the furnace by opening` a damper or dampers 33. The connection of the valves 19 and 25 enables them both to bey quickly set for either of the operations described.

From the foregoing it will be evident that my invention results in greater economy, eiclency and rapidity of operation than has been possible with prior methods. Furthermore, the heating is accomplished without the furnace gases ntacting the material.

What I claim is:

1. In a drier, a conveyer for the material under treatment, a furnace for heating said conveyer, a .preheater subjected to the furnace heat, and means for passing a gas di- 'transported by the conveyer, and then directly to the furnace and back into heat transferring relation to the conveyer.

2. In a drier, an inclined conveyer cylinder, a preheater, and valve means for selectively passing a drying fluid through the preheater and into either end of the inclined drying cylinder.

3. In a drier, a conveyer cylinder, a reheater, means for passing a drying uid through a section of the preheater and back through another section of the same into one end of the cylinder, and means for selectively passing the entire flow of gas in one direction through the preheater and into the opposite end of the cylinder.

4. In apparatus of the character described, a drying cylinder, a furnace for heating the same, an air preheater di-sposed in the path of the furnace gases, a conduit for passing air through the preheater and the drying cylinder to the furnace, valve mechanism for controlling such flow of air and including a valve at one end of the preheater for 'controlling flow through one section of or through the entire preheater7 and a valve at the opposite end of the preheater for enforcing flow through another section of the preheater or permitting flow direct to the drying cylinder.

5. In a drier, a conveyer for the material under treatment, a furnace for heating said conveyer, a preheater subjected to the heat from the furnace, means for passing a gas through the preheater over the material transported by the conveyer to the furnace, to cause -said vapor-laden air to promote combustion and add to the sensible heat of the furnace and means for returning said preheated and vapor-laden air with the products of combustion from the furnace back into heat transferring relation to the conveyer and to the preheater.

6. In a drier, a furnace, a conveyer for the material heated by said furnace and closed against the furnace gases, a preheater and means for supplying air to the furnace through said preheater and through the conveyer to cause the air after being preheated to pick up moisture from the material in the conveyer and for then passing the heated moisture-laden air combined with the furnace'gases from the furnace into heating relation with the conveyer and preheater.

7.In a drier, a conveyer, a furnace for heating the same, a preheater subjected to the furnace heat and means for passing a drying and combustion supporting gas either through the preheater and conveyer to the furnace or simply through the preheater and conveyer.

8. In a drier, a conveyer, a furnace for tenente heating the seine, e, preheeter subjected to the furnace heart and means tor pussng e, drying end combustion supporting ges either through the preheater and eonveyer to the 5 turnaree or simpiy through the preheuter und eonyeyer, seid ineens ineiuding interconnected Valves et opposite ends ot the preheeiter.

9. In e drier, e, eonyeyer, n preheuter, niesins for passing e drying duid to et seetion 10 ot the preheeter end heet: through unother tht section et' the suene into heut trunsterring retetion to one end ot the oonyeyer end nieuns tor seteetiyety pushing the entire donf ot drying Huid in one direction through the preheuter end into heet treinstel-ring retution to the opposite end ot the eonveyer.,

in Witness Whereot, t huye hereunto set rny hond this 8th dey ot Sept/einher, 1920.

GUDFREY ENGEL, he. 

